common: Move wait_ticks functions out of common.h

This function belongs in time.h so move it over and add a comment.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

drivers/timer/mpc83xx_timer.c

@@ -9,6 +9,7 @@
 #include <clk.h>
 #include <dm.h>
 #include <status_led.h>
+#include <time.h>
 #include <timer.h>
 #include <watchdog.h>